Mechanical pencil



FIG. 1 is a front perspective view of a mechanical pencil embodying my new design;

FIG. 2 is a top plan view;

FIG. 3 is a front elevational view;

FIG. 4 is a bottom plan view; and,

FIG. 5 is a side elevational view. 

The ornamental design for a mechanical pencil, as shown. 